1. Field of the Invention
The present invention relates to a snap ring, and more particularly, a snap ring with improved retention characteristics.
2. Background Art
The use of snap rings as a retention device for mechanical components is well known. Some snap rings are designated “external”, indicating their use on the outside of a component such as a shaft. Other snap rings are of the “internal” type, and are typically used inside cylindrical cavities, such as tubes, bored cylinders, and the like. When used inside a cavity, the snap ring may be provided with one of a number of different retention devices. For example, a groove may be machined into a cylinder wall, the groove being configured to retain the desired snap ring. In some cases, for example, with a relatively thin-walled tube, tabs may be formed in the tube wall to project inside the tube to retain the snap ring.
In use, a snap ring may experience an axial load; indeed, it is often the function of a snap ring to provide resistance to an axial load applied by one or more components. In such applications, it is important for the snap ring to be able to withstand the axial loading without becoming dislodged. This can be a particular problem for internal snap rings having retention devices, such as tabs, that are formed rather than machined. Specifically, forming operations often do not allow for the retention device to be reliably formed at a 90 degree angle to the cylinder wall. In many cases, the retention device will have a retaining ledge that forms an obtuse angle with the cylinder wall. Thus, as it is loaded, a snap ring may creep up the retaining ledge, thereby experiencing a reduction in diameter. The reduction in diameter may continue with additional or continued loading, until the snap ring diameter is below a minimum retaining diameter and retention is lost.
Accordingly, it is desirable to provide a snap ring having improved retention characteristics, and in particular, an internal snap ring configured to maintain retention in the presence of an axial load.